export function movePoint(point) {
  const direction = Math.floor(Math.random() * 4)
  switch (direction) {
    case 0: //上
      point.y = point.y > 0 ? point.y - 1 : point.y
      break
    case 1: //下
      point.y = point.y < 9 ? point.y + 1 : point.y
      break
    case 2: //左
      point.x = point.x > 0 ? point.x - 1 : point.x
      break
    case 3: //右
      point.x = point.x < 11 ? point.x + 1 : point.x
      break
  }
}
